Source files vs binary files: what's the purpose of providing both? [duplicate]

This question already has answers here: Difference between Groovy Binary and Source release? (3 answers) Closed 7 years ago.

here http://www.codeproject.com/KB/database/CsvReader.aspx

offers both source and binary files. If I am a programmer who needs to use开发者_C百科 the files, why should they be providing me with both? Why not just give me the source and I will compile it?

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Some people don't have the compiler, but want to run the software.

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In case the user wants to see the application run before digging into the source.

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It is convention on CodeProject to provide a working solution and source code as separate packages. Users of the site come to expect it.